OSGi is an interesting topic. Application server vendors and near-application servers like Spring are making provisions for it in their future offerings. Apache is helping lead the charge with Felix, an open source OSGi implementation. I hope to soon review a new book on the basics of OSGi, "OSGi and Apache Felix 3.0 Beginner's Guide" from Packt. Watch this space for a review in the near future.
Another interesting topic is Business Process Management. I've worked around this one for many years, and have at times used JBoss's JBPM product for my tasks. I look forward to reading another Packt title, 'jBPM Developer Guide', which promises to hold some good tips for optimal jBPM development.
BTW, how about that crazy upper/lower-case letter treatment for these two books? Totally coincidental!
The OSGi book can be found here.
The jBPM book can be found here.